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ref: f35d5ee5b036b7b4fa59b1839f52fca15b7f99f9
dir: /sys/src/cmd/audio/mp3enc/vbrquantize.c/

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/*
 *	MP3 quantization
 *
 *	Copyright (c) 1999 Mark Taylor
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/* $Id: vbrquantize.c,v 1.41 2001/03/12 07:26:08 markt Exp $ */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <assert.h>
#include "util.h"
#include "l3side.h"
#include "quantize.h"
#include "reservoir.h"
#include "quantize_pvt.h"
#include "lame-analysis.h"

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif

#undef MAXQUANTERROR


typedef union {
    float f;
    int   i;
} fi_union;

#define MAGIC_FLOAT (65536*(128))
#define MAGIC_INT    0x4b000000

#ifdef TAKEHIRO_IEEE754_HACK

#ifdef MAXQUANTERROR 
#define DUFFBLOCK() do { \
        xp = xr34[0] * sfpow34_p1; \
        xe = xr34[0] * sfpow34_eq; \
        xm = xr34[0] * sfpow34_m1; \
        if (xm > IXMAX_VAL)  \
            return -1; \
        xp += MAGIC_FLOAT; \
        xe += MAGIC_FLOAT; \
        xm += MAGIC_FLOAT; \
        fi[0].f = xp; \
        fi[1].f = xe; \
        fi[2].f = xm; \
        fi[0].f = xp + (adj43asm - MAGIC_INT)[fi[0].i]; \
        fi[1].f = xe + (adj43asm - MAGIC_INT)[fi[1].i]; \
        fi[2].f = xm + (adj43asm - MAGIC_INT)[fi[2].i]; \
        fi[0].i -= MAGIC_INT; \
        fi[1].i -= MAGIC_INT; \
        fi[2].i -= MAGIC_INT; \
        x0 = fabs(xr[0]); \
        xp = x0 - pow43[fi[0].i] * sfpow_p1; \
        xe = x0 - pow43[fi[1].i] * sfpow_eq; \
        xm = x0 - pow43[fi[2].i] * sfpow_m1; \
        xp *= xp; \
        xe *= xe; \
        xm *= xm; \
        xfsf_eq = Max(xfsf_eq, xe); \
        xfsf_p1 = Max(xfsf_p1, xp); \
        xfsf_m1 = Max(xfsf_m1, xm); \
        ++xr; \
        ++xr34; \
    } while(0)  
#else
#define DUFFBLOCK() do { \
        xp = xr34[0] * sfpow34_p1; \
        xe = xr34[0] * sfpow34_eq; \
        xm = xr34[0] * sfpow34_m1; \
        if (xm > IXMAX_VAL)  \
            return -1; \
        xp += MAGIC_FLOAT; \
        xe += MAGIC_FLOAT; \
        xm += MAGIC_FLOAT; \
        fi[0].f = xp; \
        fi[1].f = xe; \
        fi[2].f = xm; \
        fi[0].f = xp + (adj43asm - MAGIC_INT)[fi[0].i]; \
        fi[1].f = xe + (adj43asm - MAGIC_INT)[fi[1].i]; \
        fi[2].f = xm + (adj43asm - MAGIC_INT)[fi[2].i]; \
        fi[0].i -= MAGIC_INT; \
        fi[1].i -= MAGIC_INT; \
        fi[2].i -= MAGIC_INT; \
        x0 = fabs(xr[0]); \
        xp = x0 - pow43[fi[0].i] * sfpow_p1; \
        xe = x0 - pow43[fi[1].i] * sfpow_eq; \
        xm = x0 - pow43[fi[2].i] * sfpow_m1; \
        xfsf_p1 += xp * xp; \
        xfsf_eq += xe * xe; \
        xfsf_m1 += xm * xm; \
        ++xr; \
        ++xr34; \
    } while(0)  
#endif

#else

/*********************************************************************
 * XRPOW_FTOI is a macro to convert floats to ints.  
 * if XRPOW_FTOI(x) = nearest_int(x), then QUANTFAC(x)=adj43asm[x]
 *                                         ROUNDFAC= -0.0946
 *
 * if XRPOW_FTOI(x) = floor(x), then QUANTFAC(x)=asj43[x]   
 *                                   ROUNDFAC=0.4054
 *********************************************************************/
#  define QUANTFAC(rx)  adj43[rx]
#  define ROUNDFAC 0.4054
#  define XRPOW_FTOI(src,dest) ((dest) = (int)(src))


#endif


static FLOAT8
calc_sfb_noise(const FLOAT8 *xr, const FLOAT8 *xr34, const int bw, const int sf)
{
  int j;
  fi_union fi; 
  FLOAT8 temp;
  FLOAT8 xfsf=0;
  FLOAT8 sfpow,sfpow34;

  sfpow = POW20(sf+210); /*pow(2.0,sf/4.0); */
  sfpow34  = IPOW20(sf+210); /*pow(sfpow,-3.0/4.0);*/

  for ( j=0; j < bw ; ++j) {
#if 0
    int ix;
    if (xr34[j]*sfpow34 > IXMAX_VAL) return -1;
    ix=floor( xr34[j]*sfpow34);
    temp = fabs(xr[j])- pow43[ix]*sfpow;
    temp *= temp;

    if (ix < IXMAX_VAL) {
      temp2 = fabs(xr[j])- pow43[ix+1]*sfpow;
      temp2 *=temp2;
      if (temp2<temp) {
	temp=temp2;
	++ix;
      }
    }
#else
    if (xr34[j]*sfpow34 > IXMAX_VAL) return -1;

#ifdef TAKEHIRO_IEEE754_HACK
    temp   = sfpow34*xr34[j];
    temp  += MAGIC_FLOAT; 
    fi.f  = temp;
    fi.f  = temp + (adj43asm - MAGIC_INT)[fi.i];
    fi.i -= MAGIC_INT;
#else
    temp = xr34[j]*sfpow34;
    XRPOW_FTOI(temp, fi.i);
    XRPOW_FTOI(temp + QUANTFAC(fi.i), fi.i);
#endif

    temp = fabs(xr[j])- pow43[fi.i]*sfpow;
    temp *= temp;
    
#endif
    
#ifdef MAXQUANTERROR
    xfsf = Max(xfsf,temp);
#else
    xfsf += temp;
#endif
  }
#ifdef MAXQUANTERROR
  return xfsf;
#else
  return xfsf;//bw;
#endif
}




static FLOAT8
calc_sfb_noise_ave(const FLOAT8 *xr, const FLOAT8 *xr34, const int bw, const int sf)
{
    double xp;
    double xe;
    double xm;
#ifdef TAKEHIRO_IEEE754_HACK
    double x0;
#endif
    int xx[3], j;
    fi_union *fi = (fi_union *)xx; 
    FLOAT8 sfpow34_eq, sfpow34_p1, sfpow34_m1;
    FLOAT8 sfpow_eq, sfpow_p1, sfpow_m1;
    FLOAT8 xfsf_eq = 0, xfsf_p1 = 0, xfsf_m1 = 0;

    sfpow_eq = POW20(sf + 210); /*pow(2.0,sf/4.0); */
    sfpow_m1 = sfpow_eq * .8408964153;  /* pow(2,(sf-1)/4.0) */
    sfpow_p1 = sfpow_eq * 1.189207115;  
    
    sfpow34_eq = IPOW20(sf + 210); /*pow(sfpow,-3.0/4.0);*/
    sfpow34_m1 = sfpow34_eq * 1.13878863476;       /* .84089 ^ -3/4 */
    sfpow34_p1 = sfpow34_eq * 0.878126080187;

#ifdef TAKEHIRO_IEEE754_HACK
    /*
     *  loop unrolled into "Duff's Device".   Robert Hegemann
     */    
    j = (bw+3) / 4;
    switch (bw % 4) {
        default:
        case 0: do{ DUFFBLOCK();
        case 3:     DUFFBLOCK();
        case 2:     DUFFBLOCK();
        case 1:     DUFFBLOCK(); } while (--j);
    }
#else
    for (j = 0; j < bw; ++j) {

        if (xr34[j]*sfpow34_m1 > IXMAX_VAL) return -1;

        xe = xr34[j]*sfpow34_eq;
        XRPOW_FTOI(xe, fi[0].i);
        XRPOW_FTOI(xe + QUANTFAC(fi[0].i), fi[0].i);
        xe = fabs(xr[j])- pow43[fi[0].i]*sfpow_eq;
        xe *= xe;

        xp = xr34[j]*sfpow34_p1;
        XRPOW_FTOI(xp, fi[0].i);
        XRPOW_FTOI(xp + QUANTFAC(fi[0].i), fi[0].i);
        xp = fabs(xr[j])- pow43[fi[0].i]*sfpow_p1;
        xp *= xp;

        xm = xr34[j]*sfpow34_m1;
        XRPOW_FTOI(xm, fi[0].i);
        XRPOW_FTOI(xm + QUANTFAC(fi[0].i), fi[0].i);
        xm = fabs(xr[j])- pow43[fi[0].i]*sfpow_m1;
        xm *= xm;

#ifdef MAXQUANTERROR
        xfsf_eq = Max(xfsf,xm);
        xfsf_p1 = Max(xfsf_p1,xp);
        xfsf_m1 = Max(xfsf_m1,xm);
#else
        xfsf_eq += xe;
        xfsf_p1 += xp;
        xfsf_m1 += xm;
#endif
    }
#endif

    if (xfsf_eq < xfsf_p1) 
        xfsf_eq = xfsf_p1;
    if (xfsf_eq < xfsf_m1) 
        xfsf_eq = xfsf_m1;
#ifdef MAXQUANTERROR
    return xfsf_eq;
#else
    return xfsf_eq;//bw;
#endif
}



static int
find_scalefac(const FLOAT8 *xr, const FLOAT8 *xr34, const int sfb,
		     const FLOAT8 l3_xmin, const int bw)
{
  FLOAT8 xfsf;
  int i,sf,sf_ok,delsf;

  /* search will range from sf:  -209 -> 45  */
  sf = -82;
  delsf = 128;

  sf_ok=10000;
  for (i=0; i<7; i++) {
    delsf /= 2;
    xfsf = calc_sfb_noise(xr,xr34,bw,sf);

    if (xfsf < 0) {
      /* scalefactors too small */
      sf += delsf;
    }else{
      if (sf_ok==10000) sf_ok=sf;  
      if (xfsf > l3_xmin)  {
	/* distortion.  try a smaller scalefactor */
	sf -= delsf;
      }else{
	sf_ok = sf;
	sf += delsf;
      }
    }
  } 
  assert(sf_ok!=10000);
#if 0
  assert(delsf==1);  /* when for loop goes up to 7 */
#endif

  return sf;
}

static int
find_scalefac_ave(const FLOAT8 *xr, const FLOAT8 *xr34, const int sfb,
		     const FLOAT8 l3_xmin, const int bw)
{
  FLOAT8 xfsf;
  int i,sf,sf_ok,delsf;

  /* search will range from sf:  -209 -> 45  */
  sf = -82;
  delsf = 128;

  sf_ok=10000;
  for (i=0; i<7; i++) {
    delsf /= 2;
    xfsf = calc_sfb_noise_ave(xr,xr34,bw,sf);

    if (xfsf < 0) {
      /* scalefactors too small */
      sf += delsf;
    }else{
      if (sf_ok==10000) sf_ok=sf;  
      if (xfsf > l3_xmin)  {
	/* distortion.  try a smaller scalefactor */
	sf -= delsf;
      }else{
	sf_ok = sf;
	sf += delsf;
      }
    }
  } 
  assert(sf_ok!=10000);
#if 0
  assert(delsf==1);  /* when for loop goes up to 7 */
#endif

  return sf;
}



/*  ???
        How do the following tables look like for MPEG-2-LSF
                                                            ??? */



static const int max_range_short[SBPSY_s] =
{15, 15, 15, 15, 15, 15, 7, 7, 7, 7, 7, 7 };

static const int max_range_long[SBPSY_l] =
{15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7};

static const int max_range_short_lsf[SBPSY_s] =
{15, 15, 15, 15, 15, 15, 7, 7, 7, 7, 7, 7 };

/*static const int max_range_short_lsf_pretab[SBPSY_s] =
{}*/

static const int max_range_long_lsf[SBPSY_l] =
{15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7};

static const int max_range_long_lsf_pretab[SBPSY_l] =
{ 7,7,7,7,7,7, 3,3,3,3,3, 0,0,0,0, 0,0,0, 0,0,0 };
    

static int 
compute_scalefacs_short_lsf (
    int sf[SBPSY_s][3],gr_info *cod_info, int scalefac[SBPSY_s][3],int sbg[3])
{
    int maxrange, maxrange1, maxrange2, maxover;
    int sfb, i;
    int ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;

    maxover   = 0;
    maxrange1 = max_range_short_lsf[0];
    maxrange2 = max_range_short_lsf[6];


    for (i=0; i<3; ++i) {
        int maxsf1 = 0, maxsf2 = 0, minsf = 1000;
        /* see if we should use subblock gain */
        for (sfb = 0; sfb < SBPSY_s; sfb++) {
            if (sfb < 6) {
                if (maxsf1 < -sf[sfb][i]) 
                    maxsf1 = -sf[sfb][i];
            } else {
                if (maxsf2 < -sf[sfb][i]) 
                    maxsf2 = -sf[sfb][i];
            }
            if (minsf > -sf[sfb][i]) 
                minsf = -sf[sfb][i];
        }

        /* boost subblock gain as little as possible so we can
         * reach maxsf1 with scalefactors 
         * 8*sbg >= maxsf1   
         */
        maxsf1 = Max (maxsf1-maxrange1*ifqstep, maxsf2-maxrange2*ifqstep);
        sbg[i] = 0;
        if (minsf > 0) 
            sbg[i] = floor (.125*minsf + .001);
        if (maxsf1 > 0) 
            sbg[i] = Max (sbg[i], (maxsf1/8 + (maxsf1 % 8 != 0)));
        
        if (sbg[i] > 7) 
            sbg[i] = 7;


        for (sfb = 0; sfb < SBPSY_s; sfb++) {
            sf[sfb][i] += 8*sbg[i];

            if (sf[sfb][i] < 0) {
                maxrange = sfb < 6 ? maxrange1 : maxrange2;
                
                scalefac[sfb][i]
                     = -sf[sfb][i]/ifqstep + (-sf[sfb][i]%ifqstep != 0);
                
                if (scalefac[sfb][i] > maxrange)
                    scalefac[sfb][i] = maxrange;

                if (maxover < -(sf[sfb][i] + scalefac[sfb][i]*ifqstep)) 
                    maxover = -(sf[sfb][i] + scalefac[sfb][i]*ifqstep);
            }
        }
    }

    return maxover;
}

static int
compute_scalefacs_long_lsf (
              int             sf       [SBPSY_l], 
        const gr_info * const cod_info, 
              int             scalefac [SBPSY_l] )
{
    const int * max_range = max_range_long_lsf;
    int ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;
    int sfb;
    int maxover;
  

    if (cod_info->preflag) {
        max_range = max_range_long_lsf_pretab;
        for (sfb = 11; sfb < SBPSY_l; sfb++) 
            sf[sfb] += pretab[sfb] * ifqstep;
    }

    maxover = 0;
    for (sfb = 0; sfb < SBPSY_l; sfb++) {

        if (sf[sfb] < 0) {
            /* ifqstep*scalefac >= -sf[sfb], so round UP */
            scalefac[sfb] = -sf[sfb]/ifqstep  + (-sf[sfb] % ifqstep != 0);
            if (scalefac[sfb] > max_range[sfb]) 
                scalefac[sfb] = max_range[sfb];
      
            /* sf[sfb] should now be positive: */
            if (-(sf[sfb] + scalefac[sfb]*ifqstep) > maxover) {
                maxover = -(sf[sfb] + scalefac[sfb]*ifqstep);
            }
        }
    }

    return maxover;
}


/*
    sfb=0..5  scalefac < 16 
    sfb>5     scalefac < 8

    ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;
    ol_sf =  (cod_info->global_gain-210.0);
    ol_sf -= 8*cod_info->subblock_gain[i];
    ol_sf -= ifqstep*scalefac[gr][ch].s[sfb][i];

*/
static int 
compute_scalefacs_short(int sf[SBPSY_s][3],gr_info *cod_info,
int scalefac[SBPSY_s][3],int sbg[3])
{
  int maxrange,maxrange1,maxrange2,maxover;
  int sfb,i;
  int ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;

  maxover=0;
  maxrange1 = 15;
  maxrange2 = 7;


  for (i=0; i<3; ++i) {
    int maxsf1=0,maxsf2=0,minsf=1000;
    /* see if we should use subblock gain */
    for ( sfb = 0; sfb < SBPSY_s; sfb++ ) {
      if (sfb < 6) {
	if (-sf[sfb][i]>maxsf1) maxsf1 = -sf[sfb][i];
      } else {
	if (-sf[sfb][i]>maxsf2) maxsf2 = -sf[sfb][i];
      }
      if (-sf[sfb][i]<minsf) minsf = -sf[sfb][i];
    }

    /* boost subblock gain as little as possible so we can
     * reach maxsf1 with scalefactors 
     * 8*sbg >= maxsf1   
     */
    maxsf1 = Max(maxsf1-maxrange1*ifqstep,maxsf2-maxrange2*ifqstep);
    sbg[i]=0;
    if (minsf >0 ) sbg[i] = floor(.125*minsf + .001);
    if (maxsf1 > 0)  sbg[i] = Max(sbg[i],(maxsf1/8 + (maxsf1 % 8 != 0)));
    if (sbg[i] > 7) sbg[i]=7;


    for ( sfb = 0; sfb < SBPSY_s; sfb++ ) {
      sf[sfb][i] += 8*sbg[i];

      if (sf[sfb][i] < 0) {
	maxrange = sfb < 6 ? maxrange1 : maxrange2;
        scalefac[sfb][i]= -sf[sfb][i]/ifqstep + (-sf[sfb][i]%ifqstep != 0);
	if (scalefac[sfb][i]>maxrange) scalefac[sfb][i]=maxrange;
	
	if (-(sf[sfb][i] + scalefac[sfb][i]*ifqstep) >maxover)  {
	  maxover=-(sf[sfb][i] + scalefac[sfb][i]*ifqstep);
	}
      }
    }
  }

  return maxover;
}



/*
	  ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;
	  ol_sf =  (cod_info->global_gain-210.0);
	  ol_sf -= ifqstep*scalefac[gr][ch].l[sfb];
	  if (cod_info->preflag && sfb>=11) 
	  ol_sf -= ifqstep*pretab[sfb];
*/
static int
compute_scalefacs_long(int sf[SBPSY_l],gr_info *cod_info,int scalefac[SBPSY_l])
{
  int sfb;
  int maxover;
  int ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;
  

  if (cod_info->preflag)
    for ( sfb = 11; sfb < SBPSY_l; sfb++ ) 
      sf[sfb] += pretab[sfb]*ifqstep;


  maxover=0;
  for ( sfb = 0; sfb < SBPSY_l; sfb++ ) {

    if (sf[sfb]<0) {
      /* ifqstep*scalefac >= -sf[sfb], so round UP */
      scalefac[sfb]= -sf[sfb]/ifqstep + (-sf[sfb] % ifqstep != 0);
      if (scalefac[sfb] > max_range_long[sfb]) scalefac[sfb]=max_range_long[sfb];
      
      /* sf[sfb] should now be positive: */
      if (  -(sf[sfb] + scalefac[sfb]*ifqstep)  > maxover) {
	maxover = -(sf[sfb] + scalefac[sfb]*ifqstep);
      }
    }
  }

  return maxover;
}
  
  






/************************************************************************
 *
 * quantize and encode with the given scalefacs and global gain
 *
 * compute scalefactors, l3_enc, and return number of bits needed to encode
 *
 *
 ************************************************************************/

static int
VBR_quantize_granule( 
          lame_global_flags *gfp,
          FLOAT8                 xr34[576], 
          int                    l3_enc[576],
    const III_psy_ratio  * const ratio,  
          III_scalefac_t * const scalefac, 
    const int gr, 
    const int ch)
{
  lame_internal_flags *gfc=gfp->internal_flags;
  int status;
  gr_info *cod_info;  
  III_side_info_t * l3_side;
  l3_side = &gfc->l3_side;
  cod_info = &l3_side->gr[gr].ch[ch].tt;


  /* encode scalefacs */
  if ( gfc->is_mpeg1 ) 
    status=scale_bitcount(scalefac, cod_info);
  else
    status=scale_bitcount_lsf(gfc,scalefac, cod_info);

  if (status!=0) {
    return -1;
  }
  
  /* quantize xr34 */
  cod_info->part2_3_length = count_bits(gfc,l3_enc,xr34,cod_info);
  if (cod_info->part2_3_length >= LARGE_BITS) return -2;
  cod_info->part2_3_length += cod_info->part2_length;


  if (gfc->use_best_huffman==1) {
    best_huffman_divide(gfc, gr, ch, cod_info, l3_enc);
  }
  return 0;
}


  
/***********************************************************************
 *
 *      calc_short_block_vbr_sf()
 *      calc_long_block_vbr_sf()
 *
 *  Mark Taylor 2000-??-??
 *  Robert Hegemann 2000-10-25 made functions of it
 *
 ***********************************************************************/
static const int MAX_SF_DELTA = 4;    

static int 
short_block_vbr_sf (
    const lame_internal_flags        * const gfc,
    const III_psy_xmin   * const l3_xmin,
    const FLOAT8                 xr34_orig[576],
    const FLOAT8                 xr34     [576],
          III_scalefac_t * const vbrsf )
{
     int j, sfb, b;
    int vbrmax = -10000; /* initialize for maximum search */
  
    for (j = 0, sfb = 0; sfb < SBMAX_s; sfb++) {
        for (b = 0; b < 3; b++) {
	    const  int start = gfc->scalefac_band.s[ sfb ];
	    const  int end   = gfc->scalefac_band.s[ sfb+1 ];
	    const  int width = end - start;
	    
            vbrsf->s[sfb][b] = find_scalefac_ave (&xr34[j], &xr34_orig[j],
                                              sfb, l3_xmin->s[sfb][b], width);
            j += width;
        }
    }
    
    for (sfb = 0; sfb < SBMAX_s; sfb++) {
        for (b = 0; b < 3; b++) {
	    if (sfb > 0) 
	        if (vbrsf->s[sfb][b] > vbrsf->s[sfb-1][b]+MAX_SF_DELTA)
                    vbrsf->s[sfb][b] = vbrsf->s[sfb-1][b]+MAX_SF_DELTA;
	    if (sfb < SBMAX_s-1) 
	        if (vbrsf->s[sfb][b] > vbrsf->s[sfb+1][b]+MAX_SF_DELTA)
                    vbrsf->s[sfb][b] = vbrsf->s[sfb+1][b]+MAX_SF_DELTA;
            if (vbrmax < vbrsf->s[sfb][b])
                vbrmax = vbrsf->s[sfb][b];
        }
    }

    return vbrmax;
}



static int 
long_block_vbr_sf (
    const lame_internal_flags        * const gfc,
    const III_psy_xmin   * const l3_xmin,
    const FLOAT8                 xr34_orig[576],
    const FLOAT8                 xr34     [576],
          III_scalefac_t * const vbrsf )
{
     int sfb;
    int vbrmax = -10000; /* initialize for maximum search */
    
    for (sfb = 0; sfb < SBMAX_l; sfb++) {
        const  int start = gfc->scalefac_band.l[ sfb ];
        const  int end   = gfc->scalefac_band.l[ sfb+1 ];
        const  int width = end - start;
        
        vbrsf->l[sfb] = find_scalefac_ave (&xr34[start], &xr34_orig[start],
                                               sfb, l3_xmin->l[sfb], width);
    }
    
    for (sfb = 0; sfb < SBMAX_l; sfb++) {
        if (sfb > 0) 
	    if (vbrsf->l[sfb] > vbrsf->l[sfb-1]+MAX_SF_DELTA)
                vbrsf->l[sfb] = vbrsf->l[sfb-1]+MAX_SF_DELTA;
        if (sfb < SBMAX_l-1) 
	    if (vbrsf->l[sfb] > vbrsf->l[sfb+1]+MAX_SF_DELTA)
                vbrsf->l[sfb] = vbrsf->l[sfb+1]+MAX_SF_DELTA;
        if (vbrmax < vbrsf->l[sfb]) 
            vbrmax = vbrsf->l[sfb];
    }
        
    return vbrmax;
}


    /* a variation for vbr-mtrh */
static int 
short_block_sf (
    const lame_internal_flags        * const gfc,
    const III_psy_xmin   * const l3_xmin,
    const FLOAT8                 xr34_orig[576],
    const FLOAT8                 xr34     [576],
          III_scalefac_t * const vbrsf )
{
     int j, sfb, b;
    int vbrmean, vbrmin, vbrmax;
    int sf_cache[SBMAX_s];
  
    for (j = 0, sfb = 0; sfb < SBMAX_s; sfb++) {
        for (b = 0; b < 3; b++) {
	    const  int start = gfc->scalefac_band.s[ sfb ];
	    const  int end   = gfc->scalefac_band.s[ sfb+1 ];
	    const  int width = end - start;
	    
            if (0 == gfc->noise_shaping_amp) {
                /*  the faster and sloppier mode to use at lower quality
                 */
                vbrsf->s[sfb][b] = find_scalefac (&xr34[j], &xr34_orig[j], sfb,
                                              l3_xmin->s[sfb][b], width);
	    }
            else {
                /*  the slower and better mode to use at higher quality
                 */
                vbrsf->s[sfb][b] = find_scalefac_ave (&xr34[j], &xr34_orig[j],
                                              sfb, l3_xmin->s[sfb][b], width);
            }
            j += width;
        }
    }
    
    vbrmax = -10000;
    
    for (b = 0; b < 3; b++) { 

        /*  make working copy, select_kth_int will reorder!
         */
        for (sfb = 0; sfb < SBMAX_s; sfb++) 
            sf_cache[sfb] = vbrsf->s[sfb][b];
        
        /*  find median value, take it as mean 
         */
        vbrmean = select_kth_int (sf_cache, SBMAX_s, (SBMAX_s+1)/2);
        
        /*  get min value
         */
        vbrmin = 10000;
        for (sfb = 0; sfb < SBMAX_s; sfb++) { 
            if (vbrmin > vbrsf->s[sfb][b])
                vbrmin = vbrsf->s[sfb][b];
        }
        
        /*  patch sfb12
         */
        vbrsf->s[SBPSY_s][b] = Min (vbrsf->s[SBPSY_s][b], vbrmean);
        vbrsf->s[SBPSY_s][b] = Max (vbrsf->s[SBPSY_s][b], vbrmin-(vbrmean-vbrmin));
        
        /*  cut peaks
         */
        for (sfb = 0; sfb < SBMAX_s; sfb++) {
            if (vbrsf->s[sfb][b] > vbrmean+(vbrmean-vbrmin))
                vbrsf->s[sfb][b] = vbrmean+(vbrmean-vbrmin);
        }
        
        /*  get max value
         */
        for (sfb = 0; sfb < SBMAX_s; sfb++) { 
            if (vbrmax < vbrsf->s[sfb][b])
                vbrmax = vbrsf->s[sfb][b];
        }
    }
    
    return vbrmax;
}


    /* a variation for vbr-mtrh */
static int 
long_block_sf (
    const lame_internal_flags        * const gfc,
    const III_psy_xmin   * const l3_xmin,
    const FLOAT8                 xr34_orig[576],
    const FLOAT8                 xr34     [576],
          III_scalefac_t * const vbrsf )
{
     int sfb;
    int vbrmean, vbrmin, vbrmax;
    int sf_cache[SBMAX_l];
    
    for (sfb = 0; sfb < SBMAX_l; sfb++) {
        const  int start = gfc->scalefac_band.l[ sfb ];
        const  int end   = gfc->scalefac_band.l[ sfb+1 ];
        const  int width = end - start;
        
        if (0 == gfc->noise_shaping_amp) {
            /*  the faster and sloppier mode to use at lower quality
             */
            vbrsf->l[sfb] = find_scalefac (&xr34[start], &xr34_orig[start], 
                                           sfb, l3_xmin->l[sfb], width);
        }
        else {
            /*  the slower and better mode to use at higher quality
             */
            vbrsf->l[sfb] = find_scalefac_ave (&xr34[start], &xr34_orig[start],
                                               sfb, l3_xmin->l[sfb], width);
        }
    }
    
    /*  make working copy, select_kth_int will reorder!
     */
    for (sfb = 0; sfb < SBMAX_l; sfb++)
        sf_cache[sfb] = vbrsf->l[sfb];
    
    /*  find median value, take it as mean 
     */
    vbrmean = select_kth_int (sf_cache, SBMAX_l, (SBMAX_l+1)/2);

    /*  get min value
     */
    vbrmin = +10000;
    for (sfb = 0; sfb < SBMAX_l; sfb++) {
        if (vbrmin > vbrsf->l[sfb])
            vbrmin = vbrsf->l[sfb];
    }
    
    /*  patch sfb21
     */
    vbrsf->l[SBPSY_l] = Min (vbrsf->l[SBPSY_l], vbrmean);
    vbrsf->l[SBPSY_l] = Max (vbrsf->l[SBPSY_l], vbrmin-(vbrmean-vbrmin));
    
    /*  cut peaks
     */
    for (sfb = 0; sfb < SBMAX_l; sfb++) {
        if (vbrsf->l[sfb] > vbrmean+(vbrmean-vbrmin))
            vbrsf->l[sfb] = vbrmean+(vbrmean-vbrmin);
    }
    
    /*  get max value
     */
    vbrmax = -10000;
    for (sfb = 0; sfb < SBMAX_l; sfb++) {
        if (vbrmax < vbrsf->l[sfb]) 
            vbrmax = vbrsf->l[sfb];
    }
        
    return vbrmax;
}



/******************************************************************
 *
 *  short block scalefacs
 *
 ******************************************************************/

static void 
short_block_scalefacs (
       lame_global_flags *gfp,
          gr_info        * const cod_info,
          III_scalefac_t * const scalefac,
          III_scalefac_t * const vbrsf,
          int            * const VBRmax )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    const int * max_range;
     int sfb, b;
    int maxover, maxover0, maxover1, mover;
    int v0, v1;
    int minsfb;
    int vbrmax = *VBRmax;
    
    max_range = gfc->is_mpeg1 ? max_range_short : max_range_short_lsf;
    
    maxover0 = 0;
    maxover1 = 0;
    for (sfb = 0; sfb < SBPSY_s; sfb++) {
        for (b = 0; b < 3; b++) {
            v0 = (vbrmax - vbrsf->s[sfb][b]) - (4*14 + 2*max_range[sfb]);
            v1 = (vbrmax - vbrsf->s[sfb][b]) - (4*14 + 4*max_range[sfb]);
            if (maxover0 < v0)
                maxover0 = v0;
            if (maxover1 < v1)
                maxover1 = v1;
        }
    }

    if (gfc->noise_shaping == 2)
        /* allow scalefac_scale=1 */
        mover = Min (maxover0, maxover1);
    else
        mover = maxover0; 

    vbrmax   -= mover;
    maxover0 -= mover;
    maxover1 -= mover;

    if (maxover0 == 0) 
        cod_info->scalefac_scale = 0;
    else if (maxover1 == 0)
        cod_info->scalefac_scale = 1;

    /* sf =  (cod_info->global_gain-210.0) */
    cod_info->global_gain = vbrmax + 210;
    assert(cod_info->global_gain < 256);
    
    if (vbr_mtrh == gfp->VBR && cod_info->global_gain > 1) {
        /*  just to be safe, reduce global_gain by one
         */
        cod_info->global_gain -= 1; 
    }
    
    if (cod_info->global_gain > 255)
        cod_info->global_gain = 255;

    for (sfb = 0; sfb < SBPSY_s; sfb++) {
        for (b = 0; b < 3; b++) {
            vbrsf->s[sfb][b] -= vbrmax;
        }
    }
    if ( gfc->is_mpeg1 ) 
        maxover = compute_scalefacs_short (vbrsf->s, cod_info, scalefac->s,
                                           cod_info->subblock_gain);
    else
        maxover = compute_scalefacs_short_lsf (vbrsf->s, cod_info, scalefac->s,
                                               cod_info->subblock_gain);

    assert (maxover <= 0);

    /* adjust global_gain so at least 1 subblock gain = 0 */
    minsfb = 999; /* prepare for minimum search */
    for (b = 0; b < 3; b++) 
        if (minsfb > cod_info->subblock_gain[b])
            minsfb = cod_info->subblock_gain[b];
    
    if (minsfb > cod_info->global_gain/8)
        minsfb = cod_info->global_gain/8;
    
    vbrmax                -= 8*minsfb; 
    cod_info->global_gain -= 8*minsfb;
    
    for (b = 0; b < 3; b++)
        cod_info->subblock_gain[b] -= minsfb;
        
    *VBRmax = vbrmax;
}



/******************************************************************
 *
 *  long block scalefacs
 *
 ******************************************************************/

static void 
long_block_scalefacs (
    lame_global_flags *gfp,
          gr_info        * const cod_info,
          III_scalefac_t * const scalefac,
          III_scalefac_t * const vbrsf,
          int            * const VBRmax )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    const int * max_range;
    const int * max_rangep;
     int sfb;
    int maxover, maxover0, maxover1, maxover0p, maxover1p, mover;
    int v0, v1, v0p, v1p;
    int vbrmax = *VBRmax;

    max_range  = gfc->is_mpeg1 ? max_range_long : max_range_long_lsf;
    max_rangep = gfc->is_mpeg1 ? max_range_long : max_range_long_lsf_pretab;
    
    maxover0  = 0;
    maxover1  = 0;
    maxover0p = 0; /* pretab */
    maxover1p = 0; /* pretab */
       
    for ( sfb = 0; sfb < SBPSY_l; sfb++ ) {
        v0  = (vbrmax - vbrsf->l[sfb]) - 2*max_range[sfb];
        v1  = (vbrmax - vbrsf->l[sfb]) - 4*max_range[sfb];
        v0p = (vbrmax - vbrsf->l[sfb]) - 2*(max_rangep[sfb]+pretab[sfb]);
        v1p = (vbrmax - vbrsf->l[sfb]) - 4*(max_rangep[sfb]+pretab[sfb]);
        if (maxover0 < v0)
            maxover0 = v0;
        if (maxover1 < v1)
            maxover1 = v1;
        if (maxover0p < v0p)
            maxover0p = v0p;
        if (maxover1p < v1p)
            maxover1p = v1p;
    }

    mover = Min (maxover0, maxover0p);
    if (gfc->noise_shaping == 2) {
        /* allow scalefac_scale=1 */
        mover = Min (mover, maxover1);
        mover = Min (mover, maxover1p);
    }

    vbrmax    -= mover;
    maxover0  -= mover;
    maxover0p -= mover;
    maxover1  -= mover;
    maxover1p -= mover;

    if (maxover0 <= 0) {
        cod_info->scalefac_scale = 0;
        cod_info->preflag = 0;
        vbrmax -= maxover0;
    } else if (maxover0p <= 0) {
        cod_info->scalefac_scale = 0;
        cod_info->preflag = 1;
        vbrmax -= maxover0p;
    } else if (maxover1 == 0) {
        cod_info->scalefac_scale = 1;
        cod_info->preflag = 0;
    } else if (maxover1p == 0) {
        cod_info->scalefac_scale = 1;
        cod_info->preflag = 1;
    } else {
        assert(0); /* this should not happen */
    }

    /* sf =  (cod_info->global_gain-210.0) */
    cod_info->global_gain = vbrmax + 210;
    assert (cod_info->global_gain < 256);

    if (vbr_mtrh == gfp->VBR && cod_info->global_gain > 1) {
        /*  just to be safe, reduce global gain by one
         */
        cod_info->global_gain -= 1; 
    }
    
    if (cod_info->global_gain > 255) 
        cod_info->global_gain = 255;
    
    for (sfb = 0; sfb < SBPSY_l; sfb++)   
        vbrsf->l[sfb] -= vbrmax;
    
    if ( gfc->is_mpeg1 == 1 ) 
        maxover = compute_scalefacs_long (vbrsf->l, cod_info, scalefac->l);
    else
        maxover = compute_scalefacs_long_lsf (vbrsf->l, cod_info, scalefac->l);
    
    assert (maxover <= 0);
    
    *VBRmax = vbrmax;
}



/***********************************************************************
 *
 *      calc_fac()
 *
 *  Mark Taylor 2000-??-??
 *  Robert Hegemann 2000-10-20 made functions of it
 *
 ***********************************************************************/

static FLOAT8 calc_fac ( const int ifac )
{
    if (ifac+210 < Q_MAX) 
        return 1/IPOW20 (ifac+210);
    else
        return pow (2.0, 0.75*ifac/4.0);
}



/***********************************************************************
 *
 *  quantize xr34 based on scalefactors
 *
 *  calc_short_block_xr34      
 *  calc_long_block_xr34
 *
 *  Mark Taylor 2000-??-??
 *  Robert Hegemann 2000-10-20 made functions of them
 *
 ***********************************************************************/

static void
short_block_xr34 ( 
    const lame_internal_flags        * const gfc,
    const gr_info        * const cod_info,
    const III_scalefac_t * const scalefac, 
    const FLOAT8                 xr34_orig[576],
          FLOAT8                 xr34     [576] )
{
     int sfb, l, j, b;
    int    ifac, ifqstep, start, end;
    FLOAT8 fac;

    /* even though there is no scalefactor for sfb12
     * subblock gain affects upper frequencies too, that's why
     * we have to go up to SBMAX_s
     */
    ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;
    for ( j = 0, sfb = 0; sfb < SBMAX_s; sfb++ ) {
        start = gfc->scalefac_band.s[ sfb ];
        end   = gfc->scalefac_band.s[ sfb+1 ];
        for (b = 0; b < 3; b++) {
            ifac = 8*cod_info->subblock_gain[b]+ifqstep*scalefac->s[sfb][b];
            fac = calc_fac( ifac );
            /*
             *  loop unrolled into "Duff's Device".  Robert Hegemann
             */
            l = (end-start+7) / 8;
            switch ((end-start) % 8) {
                default:
                case 0: do{ xr34[j] = xr34_orig[j]*fac; j++;
                case 7:     xr34[j] = xr34_orig[j]*fac; j++;
                case 6:     xr34[j] = xr34_orig[j]*fac; j++;
                case 5:     xr34[j] = xr34_orig[j]*fac; j++;
                case 4:     xr34[j] = xr34_orig[j]*fac; j++;
                case 3:     xr34[j] = xr34_orig[j]*fac; j++;
                case 2:     xr34[j] = xr34_orig[j]*fac; j++;
                case 1:     xr34[j] = xr34_orig[j]*fac; j++; } while (--l);
            }
        }
    }
}



static void 
long_block_xr34 ( 
    const lame_internal_flags        * const gfc,
    const gr_info        * const cod_info,
    const III_scalefac_t * const scalefac, 
    const FLOAT8                 xr34_orig[576],
          FLOAT8                 xr34     [576] )
{ 
     int sfb, l, j;
    int    ifac, ifqstep, start, end;
    FLOAT8 fac;
        
    ifqstep = ( cod_info->scalefac_scale == 0 ) ? 2 : 4;
    for ( sfb = 0; sfb < SBMAX_l; sfb++ ) {
        
        ifac = ifqstep*scalefac->l[sfb];
        if (cod_info->preflag)
            ifac += ifqstep*pretab[sfb];

        fac = calc_fac( ifac );

        start = gfc->scalefac_band.l[ sfb ];
        end   = gfc->scalefac_band.l[ sfb+1 ];
        /*
         *  loop unrolled into "Duff's Device".  Robert Hegemann
         */
        j = start;
        l = (end-start+7) / 8;
        switch ((end-start) % 8) {
            default:
            case 0: do{ xr34[j] = xr34_orig[j]*fac; j++;
            case 7:     xr34[j] = xr34_orig[j]*fac; j++;
            case 6:     xr34[j] = xr34_orig[j]*fac; j++;
            case 5:     xr34[j] = xr34_orig[j]*fac; j++;
            case 4:     xr34[j] = xr34_orig[j]*fac; j++;
            case 3:     xr34[j] = xr34_orig[j]*fac; j++;
            case 2:     xr34[j] = xr34_orig[j]*fac; j++;
            case 1:     xr34[j] = xr34_orig[j]*fac; j++; } while (--l);
        }
    }
}









/************************************************************************
 *
 * VBR_noise_shaping()
 *
 * compute scalefactors, l3_enc, and return number of bits needed to encode
 *
 * return code:    0   scalefactors were found with all noise < masking
 *
 *               n>0   scalefactors required too many bits.  global gain
 *                     was decreased by n
 *                     If n is large, we should probably recompute scalefacs
 *                     with a lower quality.
 *
 *               n<0   scalefactors used less than minbits.
 *                     global gain was increased by n.  
 *                     If n is large, might want to recompute scalefacs
 *                     with a higher quality setting?
 *
 ************************************************************************/
static int
VBR_noise_shaping (
    lame_global_flags *gfp,
    FLOAT8             xr       [576], 
    FLOAT8             xr34orig [576],
    III_psy_ratio     *ratio,
    int                l3_enc   [576], 
    int                digital_silence, 
    int                minbits,
    int                maxbits,
    III_scalefac_t    *scalefac,
    III_psy_xmin      *l3_xmin,
    int                gr,
    int                ch )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_scalefac_t save_sf;
    III_scalefac_t vbrsf;
    gr_info *cod_info;  
    FLOAT8 xr34[576];
    int shortblock;
    int vbrmax;
    int global_gain_adjust = 0;

    cod_info   = &gfc->l3_side.gr[gr].ch[ch].tt;
    shortblock = (cod_info->block_type == SHORT_TYPE);
  
    if (shortblock)
        vbrmax = short_block_vbr_sf (gfc, l3_xmin, xr34orig, xr, &vbrsf);  
    else
        vbrmax = long_block_vbr_sf (gfc, l3_xmin, xr34orig, xr, &vbrsf);  

    /* save a copy of vbrsf, incase we have to recomptue scalefacs */
    memcpy (&save_sf, &vbrsf, sizeof(III_scalefac_t));

    do { 
        memset (scalefac, 0, sizeof(III_scalefac_t));
        
        if (shortblock) {
            short_block_scalefacs (gfp, cod_info, scalefac, &vbrsf, &vbrmax);
            short_block_xr34      (gfc, cod_info, scalefac, xr34orig, xr34);
        } else {
            long_block_scalefacs (gfp, cod_info, scalefac, &vbrsf, &vbrmax);
            long_block_xr34      (gfc, cod_info, scalefac, xr34orig, xr34);
        } 
        VBR_quantize_granule (gfp, xr34, l3_enc, ratio, scalefac, gr, ch);

        
        /* decrease noise until we use at least minbits
         */
        if (cod_info->part2_3_length < minbits) {
            if (digital_silence) break;  
            //if (cod_info->part2_3_length == cod_info->part2_length) break;
            if (vbrmax+210 == 0) break;
            
            /* decrease global gain, recompute scale factors */
            --vbrmax;
            --global_gain_adjust;
            memcpy (&vbrsf, &save_sf, sizeof(III_scalefac_t));
        }

    } while (cod_info->part2_3_length < minbits);

    /* inject noise until we meet our bit limit
     */
    while (cod_info->part2_3_length > Min (maxbits, MAX_BITS)) {
        /* increase global gain, keep existing scale factors */
        ++cod_info->global_gain;
        if (cod_info->global_gain > 255) 
            ERRORF (gfc,"%ld impossible to encode ??? frame! bits=%d\n",
                    //  gfp->frameNum, cod_info->part2_3_length);
                             -1,       cod_info->part2_3_length);
        VBR_quantize_granule (gfp, xr34, l3_enc, ratio, scalefac, gr, ch);

        ++global_gain_adjust;
    }

    return global_gain_adjust;
}



/************************************************************************
 *
 *  VBR_noise_shaping2()
 *
 *  may result in a need of too many bits, then do it CBR like
 *
 *  Robert Hegemann 2000-10-25
 *
 ***********************************************************************/
 
int
VBR_noise_shaping2 (
    lame_global_flags        *gfp,
    FLOAT8                 xr       [576], 
    FLOAT8                 xr34orig [576],
    III_psy_ratio  * const ratio,
    int                    l3_enc   [576], 
    int                    digital_silence, 
    int                    minbits,
    int                    maxbits,
    III_scalefac_t * const scalefac,
    III_psy_xmin   * const l3_xmin,
    int                    gr,
    int                    ch )
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_scalefac_t vbrsf;
    gr_info *cod_info;  
    FLOAT8 xr34[576];
    int shortblock, ret, bits, huffbits;
    int vbrmax, best_huffman = gfc->use_best_huffman;

    cod_info   = &gfc->l3_side.gr[gr].ch[ch].tt;
    shortblock = (cod_info->block_type == SHORT_TYPE);
      
    if (shortblock) {
        vbrmax = short_block_sf (gfc, l3_xmin, xr34orig, xr, &vbrsf);  
        short_block_scalefacs (gfp, cod_info, scalefac, &vbrsf, &vbrmax);
        short_block_xr34      (gfc, cod_info, scalefac, xr34orig, xr34);
    } else {
        vbrmax = long_block_sf (gfc, l3_xmin, xr34orig, xr, &vbrsf);  
        long_block_scalefacs (gfp, cod_info, scalefac, &vbrsf, &vbrmax);
        long_block_xr34      (gfc, cod_info, scalefac, xr34orig, xr34);
    } 
    
    gfc->use_best_huffman = 0; /* we will do it later */
 
    ret = VBR_quantize_granule (gfp, xr34, l3_enc, ratio, scalefac, gr, ch);
    
    gfc->use_best_huffman = best_huffman;

    if (ret == -1) /* Houston, we have a problem */
        return -1;

    if (cod_info->part2_3_length < minbits) {
        huffbits = minbits - cod_info->part2_length;
        bits = bin_search_StepSize (gfc, cod_info, huffbits, 
                                    gfc->OldValue[ch], xr34, l3_enc);
        gfc->OldValue[ch] = cod_info->global_gain;
        cod_info->part2_3_length  = bits + cod_info->part2_length;
    }
    if (cod_info->part2_3_length > maxbits) {
        huffbits = maxbits - cod_info->part2_length;
        bits = bin_search_StepSize (gfc, cod_info, huffbits, 
                                    gfc->OldValue[ch], xr34, l3_enc);
        gfc->OldValue[ch] = cod_info->global_gain;
        cod_info->part2_3_length = bits;
        if (bits > huffbits) {
            bits = inner_loop (gfc, cod_info, huffbits, xr34, l3_enc);
            cod_info->part2_3_length  = bits;
        }
        if (bits >= LARGE_BITS) /* Houston, we have a problem */
            return -2;
        cod_info->part2_3_length += cod_info->part2_length;
    }

    if (cod_info->part2_length >= LARGE_BITS) /* Houston, we have a problem */
        return -2;
        
    assert (cod_info->global_gain < 256);
    
    return 0;
}




void
VBR_quantize(lame_global_flags *gfp,
                FLOAT8 pe[2][2], FLOAT8 ms_ener_ratio[2],
                FLOAT8 xr[2][2][576], III_psy_ratio ratio[2][2],
                int l3_enc[2][2][576],
                III_scalefac_t scalefac[2][2])
{
  lame_internal_flags *gfc=gfp->internal_flags;
  III_psy_xmin l3_xmin[2][2];
  int minbits,maxbits,max_frame_bits,totbits,gr,ch,i,bits_ok;
  int bitsPerFrame,mean_bits;
  int analog_silence;
  FLOAT8 qadjust;
  III_side_info_t * l3_side;
  gr_info *cod_info;  
  int digital_silence[2][2];
  FLOAT8 masking_lower_db=0;
  FLOAT8 xr34[2][2][576];
  // static const FLOAT8 dbQ[10]={-6.0,-5.0,-4.0,-3.0, -2.0, -1.0, -.25, .5, 1.25, 2.0};
  /* from quantize.c VBR algorithm */
  /*static const FLOAT8 dbQ[10]=
   {-5.5,-4.25,-3.0,-2.50, -1.75, -.75, -.5, -.25, .25, .75};*/
  /* a third dbQ table ?!? */
  static const FLOAT8 dbQ[10]=
  {-6.06,-4.4,-2.9,-1.57, -0.4, 0.61, 1.45, 2.13, 2.65, 3.0};
  
  qadjust=0;   /* start with -1 db quality improvement over quantize.c VBR */

  l3_side = &gfc->l3_side;
  //gfc->ATHlower += (4-gfp->VBR_q)*4.0; 
  //if (gfc->ATHlower < 0) gfc->ATHlower=0;


  /* now find out: if the frame can be considered analog silent
   *               if each granule can be considered digital silent
   * and calculate l3_xmin and the fresh xr34 array
   */

  assert( gfp->VBR_q <= 9 );
  assert( gfp->VBR_q >= 0 );
  analog_silence=1;
  for (gr = 0; gr < gfc->mode_gr; gr++) {
    /* copy data to be quantized into xr */
    if (gfc->mode_ext==MPG_MD_MS_LR) {
      ms_convert(xr[gr],xr[gr]);
    }
    for (ch = 0; ch < gfc->channels_out; ch++) {
      /* if in the following sections the quality would not be adjusted
       * then we would only have to call calc_xmin once here and
       * could drop subsequently calls (rh 2000/07/17)
       */
      int over_ath;
      cod_info = &l3_side->gr[gr].ch[ch].tt;
      cod_info->part2_3_length=LARGE_BITS;
      
      if (cod_info->block_type == SHORT_TYPE) {
          cod_info->sfb_lmax = 0; /* No sb*/
          cod_info->sfb_smin = 0;
      } else {
          /* MPEG 1 doesnt use last scalefactor band */
          cod_info->sfb_lmax = SBPSY_l;
          cod_info->sfb_smin = SBPSY_s;    /* No sb */
	  if (cod_info->mixed_block_flag) {
	    cod_info->sfb_lmax        = 8;
	    cod_info->sfb_smin        = 3;
	  }
      }
      
      /* quality setting */
      masking_lower_db = dbQ[gfp->VBR_q];
      if (pe[gr][ch]>750) {
        masking_lower_db -= Min(10,4*(pe[gr][ch]-750.)/750.);
      }
      gfc->masking_lower = pow(10.0,masking_lower_db/10);
      
      /* masking thresholds */
      over_ath = calc_xmin(gfp,xr[gr][ch],&ratio[gr][ch],cod_info,&l3_xmin[gr][ch]);
      
      /* if there are bands with more energy than the ATH 
       * then we say the frame is not analog silent */
      if (over_ath) {
        analog_silence = 0;
      }
      
      /* if there is no line with more energy than 1e-20
       * then this granule is considered to be digital silent
       * plus calculation of xr34 */
      digital_silence[gr][ch] = 1;
      for(i=0;i<576;i++) {
        FLOAT8 temp=fabs(xr[gr][ch][i]);
        xr34[gr][ch][i]=sqrt(sqrt(temp)*temp);
        digital_silence[gr][ch] &= temp < 1E-20;
      }
    } /* ch */
  }  /* gr */

  
  /* compute minimum allowed bits from minimum allowed bitrate */
  if (analog_silence) {
    gfc->bitrate_index=1;
  } else {
    gfc->bitrate_index=gfc->VBR_min_bitrate;
  }
  getframebits(gfp, &bitsPerFrame, &mean_bits);
  minbits = (mean_bits/gfc->channels_out);

  /* compute maximum allowed bits from max allowed bitrate */
  gfc->bitrate_index=gfc->VBR_max_bitrate;
  getframebits(gfp, &bitsPerFrame, &mean_bits);
  max_frame_bits = ResvFrameBegin(gfp, l3_side, mean_bits, bitsPerFrame);
  maxbits=2.5*(mean_bits/gfc->channels_out);

  {
  /* compute a target  mean_bits based on compression ratio 
   * which was set based on VBR_q  
   */
  int bit_rate = gfp->out_samplerate*16*gfc->channels_out/(1000.0*gfp->compression_ratio);
  bitsPerFrame = (bit_rate*gfp->framesize*1000)/gfp->out_samplerate;
  mean_bits = (bitsPerFrame - 8*gfc->sideinfo_len) / gfc->mode_gr;
  }


  minbits = Max(minbits,125);
  minbits=Max(minbits,.40*(mean_bits/gfc->channels_out));
  maxbits=Min(maxbits,2.5*(mean_bits/gfc->channels_out));







  /* 
   * loop over all ch,gr, encoding anything with bits > .5*(max_frame_bits/4)
   *
   * If a particular granule uses way too many bits, it will be re-encoded
   * on the next iteration of the loop (with a lower quality setting).  
   * But granules which dont use
   * use too many bits will not be re-encoded.
   *
   * minbits:  minimum allowed bits for 1 granule 1 channel
   * maxbits:  maximum allowwed bits for 1 granule 1 channel
   * max_frame_bits:  maximum allowed bits for entire frame
   * (max_frame_bits/4)   estimate of average bits per granule per channel
   * 
   */

  do {
  
    totbits=0;
    for (gr = 0; gr < gfc->mode_gr; gr++) {
      int minbits_lr[2];
      minbits_lr[0]=minbits;
      minbits_lr[1]=minbits;

#if 0
      if (gfc->mode_ext==MPG_MD_MS_LR) {
        FLOAT8 fac;
        fac = .33*(.5-ms_ener_ratio[gr])/.5;
        if (fac<0) fac=0;
        if (fac>.5) fac=.5;
        minbits_lr[0] = (1+fac)*minbits;
        minbits_lr[1] = Max(125,(1-fac)*minbits);
      }
#endif


      for (ch = 0; ch < gfc->channels_out; ch++) { 
        int adjusted,shortblock;
        cod_info = &l3_side->gr[gr].ch[ch].tt;
        
        /* ENCODE this data first pass, and on future passes unless it uses
         * a very small percentage of the max_frame_bits  */
        if (cod_info->part2_3_length > (max_frame_bits/(2*gfc->channels_out*gfc->mode_gr))) {
  
          shortblock = (cod_info->block_type == SHORT_TYPE);
  
          /* Adjust allowed masking based on quality setting */
          if (qadjust!=0 /*|| shortblock*/) {
            masking_lower_db = dbQ[gfp->VBR_q] + qadjust;

            /*
            if (shortblock) masking_lower_db -= 4;
            */
     
            if (pe[gr][ch]>750)
              masking_lower_db -= Min(10,4*(pe[gr][ch]-750.)/750.);
            gfc->masking_lower = pow(10.0,masking_lower_db/10);
            calc_xmin( gfp, xr[gr][ch], ratio[gr]+ch, cod_info, l3_xmin[gr]+ch);
          }
          
          /* digital silent granules do not need the full round trip,
           * but this can be optimized later on
           */
          adjusted = VBR_noise_shaping (gfp,xr[gr][ch],xr34[gr][ch],
                                        ratio[gr]+ch,l3_enc[gr][ch],
                                        digital_silence[gr][ch],
                                        minbits_lr[ch],
                                        maxbits,scalefac[gr]+ch,
                                        l3_xmin[gr]+ch,gr,ch);
          if (adjusted>10) {
            /* global_gain was changed by a large amount to get bits < maxbits */
            /* quality is set to high.  we could set bits = LARGE_BITS
             * to force re-encoding.  But most likely the other channels/granules
             * will also use too many bits, and the entire frame will
             * be > max_frame_bits, forcing re-encoding below.
             */
            // cod_info->part2_3_bits = LARGE_BITS;
          }
        }
        totbits += cod_info->part2_3_length;
      }
    }
    bits_ok=1;
    if (totbits>max_frame_bits) {
      /* lower quality */
      qadjust += Max(.125,Min(1,(totbits-max_frame_bits)/300.0));
      /* adjusting minbits and maxbits is necessary too
       * cos lowering quality is not enough in rare cases
       * when each granule still needs almost maxbits, it wont fit */ 
      minbits = Max(125,minbits*0.975);
      maxbits = Max(minbits,maxbits*0.975);
      //      DEBUGF("%i totbits>max_frame_bits   totbits=%i  maxbits=%i \n",gfp->frameNum,totbits,max_frame_bits);
      //      DEBUGF("next masking_lower_db = %f \n",masking_lower_db + qadjust);
      bits_ok=0;
    }
    
  } while (!bits_ok);
  


  /* find optimal scalefac storage.  Cant be done above because
   * might enable scfsi which breaks the interation loops */
  totbits=0;
  for (gr = 0; gr < gfc->mode_gr; gr++) {
    for (ch = 0; ch < gfc->channels_out; ch++) {
      best_scalefac_store(gfc, gr, ch, l3_enc, l3_side, scalefac);
      totbits += l3_side->gr[gr].ch[ch].tt.part2_3_length;
    }
  }


  

  if (analog_silence && !gfp->VBR_hard_min) {
    gfc->bitrate_index = 1;
  } else {
    gfc->bitrate_index = gfc->VBR_min_bitrate;
  }
  for( ; gfc->bitrate_index < gfc->VBR_max_bitrate; gfc->bitrate_index++ ) {

    getframebits (gfp, &bitsPerFrame, &mean_bits);
    maxbits = ResvFrameBegin(gfp, l3_side, mean_bits, bitsPerFrame);
    if (totbits <= maxbits) break;
  }
  if (gfc->bitrate_index == gfc->VBR_max_bitrate) {
    getframebits (gfp, &bitsPerFrame, &mean_bits);
    maxbits = ResvFrameBegin(gfp, l3_side, mean_bits, bitsPerFrame);
  }

  //  DEBUGF("%i total_bits=%i max_frame_bits=%i index=%i  \n",gfp->frameNum,totbits,max_frame_bits,gfc->bitrate_index);

  for (gr = 0; gr < gfc->mode_gr; gr++) {
    for (ch = 0; ch < gfc->channels_out; ch++) {
      cod_info = &l3_side->gr[gr].ch[ch].tt;


      ResvAdjust (gfc, cod_info, l3_side, mean_bits);
      
      /*******************************************************************
       * set the sign of l3_enc from the sign of xr
       *******************************************************************/
      for ( i = 0; i < 576; i++) {
        if (xr[gr][ch][i] < 0) l3_enc[gr][ch][i] *= -1;
      }
    }
  }
  ResvFrameEnd (gfc, l3_side, mean_bits);



}